Re: Language spec

At 05:50 PM 11/17/00 +0100, Sascha Schumann wrote:

    This specific problem shows that we need to do something
    about it. We are currently in a state where the
    implementation equals the language definition. The
    incompatibility list (PHP 3->4) would not have been
    necessary, if we had a formal language definition.

    Once we have such a language definition, people can still use
    side-effects of a scripting engine, but they won't be able to
    claim that those side-effects are valid. And thus, other
    language implementations would not have to simulate those
    side-effects.

I think it would be a good thing to start writing a language spec. I'm not quite if there's a standard format but it would be nice to start working on it. It will allow us to review all of the language aspects and only include things which were really meant to be. Do you think we can pull it off in a reasonable manner?

    Yes, I think so. While the language itself is not very
    complex, a commonly agreed-on language specification would
    prove very useful to the community and the continuity of PHP.

    I haven't been involved with designing a language
    specification before, so feel free to comment on this
    approach.

    Task 1: Defining the syntax of the language

        The syntax can be represented in the usual pseudo grammar
        style, which has been used by K&R and many ANSI/ISO
        language standards before.

    Task 2: Defining the semantics of the language

        This step basically comes down to defining what meaning
        the various pieces of the syntax have. I.e. the concept
        of a function, variable scopes, overloading, et cetera.

    Does it make sense to set up a separate workgroup for
    defining (a) the procedure and (b) the language spec itself?

Yes, this sounds like a good idea to me. I think we should do this in small steps. I am not familiar with other language standards and pseudo grammar but I'm sure we can pick this up quickly. Anyway, I don't want to prolong the discussion here because it's probably best to setup a forum for this (another mailing list) and then start discussing how/what/when this will work. Andi --- Andi Gutmans <andi@zend.com> http://www.zend.com/